«takes as input a sequence of phrase-structure trees and modifies their labels according to a set of rules. ... Its rule notation is flexible enough to emulate head/argument-finding rules»
J. Eisner, and G. Satta. Proceedings of the 37th annual meeting of the Association for Computational Linguistics on Computational Linguistics, page 457--464. Stroudsburg, PA, USA, Association for Computational Linguistics, (1999)